1. Field of the Invention
The present invention relates to electroanalytical methods, and particularly to an electroanalytical method for determination of phenols by cyclic voltammetry (CV) and square wave stripping voltammetry (SWASV).
2. Description of the Related Art
There is considerable interest in the determination of phenolic compounds in industrial, environmental or food samples. Additionally, detection of phenolic compounds is of considerable importance owing to their presence in a broad range of disinfectants. Chlorophenols (hereinafter, CPs), which are phenolic compounds, are ubiquitous and affect several organs in humans, and therefore CPs are considered to be a serious problem due to their known toxicity at low concentration levels. Thus, the analytical determination of CPs is of great interest in the field of environmental protection, as well as industrial process control.
Various analytical techniques have been described for determining CPs. These include chromatographic, spectrophotometric and electroanalytical methods. The chromatographic techniques, however, take longer time for separation before detection and/or need efficient compatible mobile phases with the stationary phase, and therefore consume a lot of reagents, and may even lead to environmental pollution. Similarly, the spectrophotometric methods are easily disturbed by turbidity and the color of detected components. In view of the drawbacks of the foregoing methods, electroanalytical methods for determination of phenol have attracted considerable interest, owing to their simplicity, speed, convenience and low cost. However, electroanalytical studies have shown that the electrochemical oxidation of phenols at various types of solid electrodes leads to a remarkable lowering in the phenol's oxidation rate, namely, the phenomenon of “electrode fouling” due to the low permeability and strong adhesion of a layer (film) that is formed at the electrode surface.
Moreover, it appears that in previous studies, the primary oxidation peak of phenol, which is obtained at a mild accumulation potential (+400 mV), was the only peak that was used in the electrochemical investigation and analytical determination of 2-chlorophenol when using an acetylene black film-modified glassy carbon electrode. Other phenol polymerization peaks that may be produced due to redox polymerization of phenolic compounds were never considered for any analytical investigation of phenols. Their fouling effects were considered as obstacles toward sensing of the phenolic compounds. As such, present electroanalytic methods so far have not addressed the use of the formed phenol-polymeric film that occurs during electrode fouling for a more sensitive, facile, and direct electroanalytical determination of CPs at unmodified glassy carbon electrode (hereinafter GCE) surfaces.
Thus, an electroanalytical method for determination of phenols solving the aforementioned problems is desired.